An arrangement for hermetically packing articles together with inert gas into bags has been well known which is of the type such that the periphery of each bag containing the article being packaged is airtightly enveloped in a pressure vessel, the air in the pressure vessel being expelled by suction by means of a vacuum pump, whereafter inert gas is injected into the pressure vessel, the opening of the bag being then sealed so that the article is hermetically kept in the bag.
While this known arrangement provides an advantage that a very high rate of bag displacement with gas can be achieved, it takes time to expel air from the pressure vessel, which fact is rather inconvenient from the standpoint of efficiency.
In an attempt to overcome this drawback, there has been proposed an arrangement in which a belt-like film, while being continuously transported in a longitudinal direction, is rounded by means of a tube former into a tube form and then hot welded at side edges thereof to be formed into a tube, and in which articles are filled into the tubulated film in equispaced relation and simultaneously inert gas is forcibly introduced into the film so that the air within the film is driven out under the feed pressure for the inert gas feed, the tubulated film being subsequently sealed between adjacent articles being packaged and at predetermined intervals (as disclosed in Japanese Utility Model Publication No. 46-16638 and Japanese Patent Application Laid-Open Publication No. 58-90017).
This known arrangement, wherein the air within the film is driven out under gas pressure while the film is progressively transported forward, provides greater operating efficiency as compared with the earlier mentioned arrangement using a pressure vessel. However, it is disadvantageous in that some oxygen residue is inevitable and in that greater inert gas consumption is required.